They now have had Mxy, Abra, Dark, as major foers with "magic", so when will there be another sighting of Constatine, or maybe even the Spectre or Fate?

Constantine, yes - but not live action.

Back in January they announced an animated web version for the CW Seed. Matt Ryan will be back to voice Constantine, but they're still in discussions as to whether this series will follow directly on from the live action show, or be something completely different.